本程序模拟路口的红黄绿交通灯的变化过程，用LED灯表示交通灯，并在数码管上显示当前状态剩余时间。 -- 红灯持续时间为30秒，黄灯3秒，绿灯30秒-This procedure simulated the red yellow and green traffic lights at the junction of the change process, said the traffic lights with LED lights, and digital tube displays the